Roll src/third_party/skia/ 2ab4b2b87..79a1256c2 (2 commits)

https://skia.googlesource.com/skia.git/+log/2ab4b2b871c0..79a1256c2233

$ git log 2ab4b2b87..79a1256c2 --date=short --no-merges --format='%ad %ae %s'
2017-09-12 benjaminwagner Simpler version of wait-for-device.
2017-09-12 jvanverth Add support for additional textures in GrDrawOpAtlas

Created with:
  roll-dep src/third_party/skia


Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, see:
http://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium#TOC-Failures-due-to-DEPS-rolls


CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_optional_gpu_tests_rel;master.tryserver.chromium.mac:mac_optional_gpu_tests_rel;master.tryserver.chromium.win:win_optional_gpu_tests_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel
TBR=stephana@chromium.org

Change-Id: I6e990b313f0c5a8a2740556fd45812cee0768ad9
Reviewed-on: https://chromium-review.googlesource.com/663740Reviewed-by: Skia Deps Roller <skia-deps-roller@chromium.org>
Commit-Queue: Skia Deps Roller <skia-deps-roller@chromium.org>
Cr-Commit-Position: refs/heads/master@{#501353}

DEPS

@@ -40,7 +40,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and whatever else without interference from each other.
-  'skia_revision': '2ab4b2b871c01aa3dd6d2e43883461c722f01680',
+  'skia_revision': '79a1256c2233485bd7a4833df02f16655f62fa1c',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.